CN114790274A - A kind of water-based polyurethane for condom and preparation method thereof - Google Patents

Abstract

The invention discloses waterborne polyurethane for condoms and a preparation method thereof, wherein the preparation method mainly comprises the following steps: providing a first component consisting of an isocyanate monomer and a catalyst and a second component consisting of a polymer polyol, a hydrophilic monomer and a small molecule chain extender; slowly adding the first component and the second component into a reaction container, and stirring at high temperature for reaction to obtain a polyurethane prepolymer with ultrahigh molecular weight; and then after the system is cooled, adding a neutralizer for neutralization, and then adding water for homogenizing and emulsifying to obtain the stable waterborne polyurethane emulsion. The preparation method is simple in process, and the prepared waterborne polyurethane has the characteristics of super softness and high elasticity, and is very suitable for preparing condoms.

Description

A kind of water-based polyurethane for condom and preparation method thereof

technical field

The invention belongs to the technical field of polymer materials, and in particular relates to a preparation method of water-based polyurethane used for condoms, and also relates to the water-based polyurethane used for condoms prepared by the preparation method and having super soft and high elastic properties.

Background technique

Condoms are non-drug forms of preventing conception and are the most commonly used contraceptives in the world. Natural latex has the characteristics of high elongation at break, good resilience, and low creep. It is the main raw material for making traditional condoms. However, natural latex condoms also have many problems, such as: (1) The material strength is low, causing condoms Thicker (0.036mm is its thickness limit, although some people choose natural latex from a specific origin to prepare 0.030mm condoms, but the natural latex resources in a specific origin are limited), the thermal conductivity is low, and the comfort of use still needs to be improved; (2 ) cannot completely remove the proteins that cause allergic reactions in humans; (3) In addition, recent studies have shown that natural latex condoms contain strong carcinogenic nitrosamines (mainly generated during the vulcanization molding process), so long-term frequent use, there is a possibility of inducing tumors. risk.

Due to the above problems of natural latex condoms, they are gradually replaced by polyurethane condoms. Polyurethane is a copolymer of soft and hard segment blocks, the soft segment enhances the elasticity of the polyurethane, and the hard segment increases the strength of the polyurethane. The condom made of this material adopts a solution film-forming process, and the film is dense and has a good ability to block viruses. At the same time, the strength of the polyurethane film is better than that of natural latex, and it can make thinner condoms (the thickness can be 10-30 μm); and the thermal conductivity of the polyurethane material is also better than that of natural latex, which increases the comfort of the user. However, polyurethane condoms also have obvious defects: (1) Polyurethane is also more rigid and has a small elongation (generally 500%-650%), that is, there is a big gap between flexibility and natural latex (natural latex elongation). The rate is 1300%-1500%), and at the same time, it is easy to slip during the use process, which reduces the use experience; (2) A large amount of organic solvents are used in the production process, which causes harm to the environment.

In order to make up for the defects of polyurethane condoms, water-based polyurethane materials came into being. Compared with solvent-based polyurethane, water-based polyurethane uses water as the dispersion medium, and has the characteristics of non-toxic and harmless, economical and energy-saving, safe and reliable, and is a green and environmentally friendly material. It usually has the advantages of low viscosity, high molecular weight, good applicability, etc., and has important applications in many industrial fields, such as coatings, glass fibers, paper sizing, synthetic leather, biological and film materials.

The Chinese patent application with publication number CN106750079A discloses a water-based polyurethane resin for condoms and a preparation method thereof, which is characterized in that a chain extender containing sulfonate is used, which can achieve high solid content and sag resistance. Good, but the properties of the prepared condoms are not disclosed.

The Chinese patent application with publication number CN107266645A discloses a preparation method of siloxane-modified water-based polyurethane emulsion and water-based polyurethane condom. Siloxane is used as the soft segment of polyurethane, the thickness of the prepared polyurethane condom is as low as 0.03mm or less, the elongation at break is more than 1000%, the breaking strength is more than 30MPa, and the 100% modulus is less than 2MPa.

Although the above-mentioned polyurethane condoms have made great progress, there is still a big gap compared with natural latex condoms in terms of 100% modulus (flexibility). -2MPa, while the 100% constant elongation modulus of natural latex is about 0.7MPa. This shows that polyurethane condoms are still far less flexible than natural latex condoms.

SUMMARY OF THE INVENTION

In view of this, the present invention needs to provide a preparation method of water-based polyurethane for condoms, the preparation method has simple procedures, and the prepared water-based polyurethane has the characteristics of super softness and high elasticity, and is very suitable for condoms.

In order to achieve the above object, the present invention adopts the following technical solutions:

The invention provides a preparation method of water-based polyurethane for condoms, comprising the following steps:

providing a first component consisting of 25-30 parts by weight of isocyanate monomer and 0.05-0.2 parts by weight of catalyst;

The second component is provided, which is composed of 60-70 parts by weight of polymer polyol after vacuum dehydration, 1-2 parts by weight of hydrophilic monomer and 1-2 parts by weight of small molecule chain extender;

The first component and the second component are slowly added to the reaction vessel, and the reaction is stirred at 80-90° C. to obtain an ultra-high molecular weight polyurethane prepolymer;

Cool the system to below 45°C, add 2-3 parts by weight of a neutralizing agent for neutralization, and then add water for homogeneous emulsification to obtain a stable aqueous polyurethane emulsion.

In a further scheme, the isocyanate monomer is selected from the combination of any two of dicyclohexylmethane diisocyanate, hexamethylene diisocyanate and 4,4'-diphenylmethane diisocyanate.

In a further scheme, the catalyst is selected from a mixture of bismuth carboxylate and dibutyltin dilaurosilicate.

In a further scheme, the relative molecular mass of the polymer polyol is 2000-3000.

In a further scheme, the polymer polyol is selected from one or a combination of two of polytetrahydrofuran glycol, polytetramethylene ether glycol, and polyethylene glycol.

In a further scheme, the vacuum dehydration process is specifically as follows: vacuum dehydration of the polymer polyol at 90-120° C. for 2-3 hours.

In a further scheme, the hydrophilic monomer is selected from one of dimethylol butyric acid and dimethylol propionic acid.

In a further scheme, the neutralizing agent is selected from one of triethylamine, N,N-diisopropylethylamine, triethanolamine, and N,N-dimethylethanolamine.

In a further scheme, the small molecule chain extender is selected from one of 1,3 propylene glycol, diethylene glycol, diethylaminoethanol, and 2 methyl 1,3 propylene glycol.

The present invention further provides an aqueous polyurethane for condoms, which is prepared by the aforementioned preparation method.

Compared with the prior art, the present invention has the following beneficial effects:

In the present invention, the first component is composed of isocyanate monomer and catalyst, and the second component is composed of polymer polyol, hydrophilic monomer and chain extender; then the first and second components are slowly added into the reaction vessel, stirring In the reaction, by controlling the reaction speed of the raw material components, on the one hand, the reaction can be made more smoothly, and on the other hand, it is helpful for the formation of the hard segment structure of the waterborne polyurethane, so that the waterborne polyurethane has a highly entangled fabric-like topology. When a highly entangled polyurethane long chain is stretched, the tension is transmitted along the chain and through the entanglement to many other chains to dissipate elastic energy, which endows the polyurethane with high toughness and solves the stiffness-toughness of conventional polyurethane. Conflict, making it super soft and highly elastic at the same time. Different from the polyurethane prepared by the conventional method, all the chains of the polyurethane prepared by the present invention are very long, there is no chemical cross-linking point, and the entanglement of molecular chains plays the role of sliding link, and has super soft and high elastic properties.

The water-based polyurethane prepared by the invention has ultra-high molecular weight, the average molecular weight is between 100,000 and 1,000,000, and there is no chemical cross-linking. When the highly entangled polyurethane long chain is stretched, the tension will be transmitted along the chain and through the entanglement It is transmitted to many other chains to dissipate elastic energy, thus endowing water-based polyurethane with high toughness, solving the conflict of stiffness-toughness of conventional polyurethane, making it have comprehensive properties of super softness and high elasticity at the same time, which is very suitable for condom materials.

Description of drawings

Fig. 1 is the scheme schematic diagram of preparing water-based polyurethane in a preferred embodiment of the present invention;

2 is a particle size distribution diagram of the aqueous polyurethane emulsion prepared in Example 1 of the present invention.

Detailed ways

The embodiments of the present invention will be described in detail below. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, but should not be construed as a limitation of the present invention.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention.

The first aspect of the present invention provides a preparation method of water-based polyurethane, which can be combined with FIG. 1, and the main steps are as follows:

S100, providing a first component and a second component.

Specifically, 25-30 parts by weight of isocyanate monomer and 0.05-0.2 part by weight of catalyst are mixed uniformly to form the first component, wherein, conventional isocyanate monomers in the art can be used, preferably, the isocyanate monomer is selected from For components with softer molecules and easier internal rotation, when the internal rotation barrier energy is lower, the internal rotation is less hindered, the conformational change is easier, and the flexibility is better, which can further improve the flexibility of water-based polyurethane. Examples include but are not limited to dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, etc. The embodiments of the present invention are selected from any two of the above isocyanate monomers. combination of species. The catalyst herein can be a conventional catalyst type in the field, and its function is mainly to reduce the activation energy required for the reaction to occur, and to speed up the reaction rate. In the embodiment of the present invention, the catalyst can be selected from dibutyltin dilaurate, bismuth carboxyl A kind of salt mixture, the bismuth carboxylate mixture is compounded by any two of bismuth isooctanoate, bismuth laurate and bismuth neocaprate.

Further, the second component is composed of 60-70 parts by weight of polymer polyol after vacuum dehydration, 1-2 parts by weight of hydrophilic monomer and 1-2 parts by weight of small molecule chain extender, polymer polyol The dehydration process can be adjusted according to the actual situation, as long as the purpose of dehydration of the polymer polyol can be achieved (generally, the water content is required to be lower than 0.2%). Specifically, in the embodiment of the present invention, 60-70 parts of The polymer polyol is dehydrated under vacuum at 90-120°C for 2-3h, and after cooling to 50-60°C, it is evenly mixed with 1-2 parts of hydrophilic monomer and 1-2 parts of small molecule chain extender to form the second group point. Wherein, according to the embodiment of the present invention, examples of polymer polyols that can be selected include, but are not limited to, polytetrahydrofuran diol, polytetramethylene ether diol, and polyethylene glycol, or a combination of both, preferably , the relative molecular weight of the polymer polyol is preferably 2000-3000, more preferably 2000. This is because if the polyether diol with a molecular weight exceeding 3000 is selected, although the molecular weight increases, the softness and elongation of the emulsion will increase, but the emulsion state It is unstable, and it is not easy to carry out the subsequent steps; if the polyether diol with a molecular weight lower than 2000 is selected, although its reactivity with polyisocyanate is high, the free rotation space of the molecular chain decreases due to the short segment length of small molecular polyether. , which will greatly reduce the softness of the emulsion and increase the hardness of the film. Therefore, in some specific embodiments of the present invention, preferably, the relative molecular mass of the polymer polyol is 2000-3000. The hydrophilic monomer described in this article contains a hydrophilic group, which can provide an anion-stabilized aqueous emulsion, thereby effectively improving the hydrophilic properties of the polyurethane. It is preferable to use a dimethylol containing a hydrophilic group carboxyl group and two primary hydroxyl groups. One of the butyric acid and dimethylol propionic acid. According to the embodiment of the present invention, the small molecule chain extender described herein is a small molecule diol that is not easy to form symmetry and crystallization, and the small molecule diol is a dihydric alcohol with a molecular weight in the range of 50-300 Alcohols, specific examples of which may be mentioned include, but are limited to, one of 1,3-propanediol, diethylene glycol, diethylaminoethanol, 2-methyl-1,3-propanediol; The water monomer cooperates with the chain extension, and its anionic hydrophilic group and non-ionic hydrophilic group act synergistically, which can effectively improve the permeability of film formation, thereby improving the bonding fastness of the polyurethane emulsion and the substrate. In addition, by using specific small molecular chain extenders and isocyanate monomers, flexible and effective crosslinking can be introduced between the polyurethane molecular chains, which can significantly improve the comprehensive properties of waterborne polyurethane without sacrificing its resilience.

S200, stepwise prepolymerization reaction.

Specifically, the first component and the second component are slowly added to the reaction vessel (stirring while adding), and after the first component and the second component are added, they are stirred at 80-90° C. After the reaction, a polyurethane prepolymer with ultra-high molecular weight (molecular weight between 100,000 and 1,000,000) is obtained. In this paper, the raw materials are respectively formed into the first component and the second component, and the first component and the second component are gradually prepolymerized by means of slow addition. Specifically, on the one hand, the reaction can be carried out more smoothly. ; On the other hand, it contributes to the formation of the hard segment structure of the water-based polyurethane, so that the water-based polyurethane has a highly entangled fabric-like topology, when the highly entangled polyurethane long chain is stretched, the tension will be transmitted along the chain and through The entanglement is transferred to many other chains to dissipate elastic energy, thereby endowing the polyurethane with high toughness, resolving the stiffness-toughness conflict of conventional polyurethane, making it simultaneously supersoft and highly elastic. It should be noted that, in order to ensure the flexibility of the water-based polyurethane while ensuring the reaction rate, the slowness described in this article is preferably controlled to have a dripping rate of 5-10 mL/min. The method of dripping or injection is preferably the injection method, which is easy to control. Further, in some specific embodiments of the present invention, the stirring rate is preferably 150-300 r/min. In this step, the molecular weight of the polyurethane prepolymer can be controlled by controlling the temperature, stirring rate, component adding rate and reaction time.

S300, neutralization, emulsification.

Specifically, the polyurethane prepolymer is cooled to below 45° C., 2-3 parts by weight of a neutralizing agent is added for neutralization, and then water is added for homogeneous emulsification to obtain a stable aqueous polyurethane emulsion. The hydrophilic monomer is neutralized by adding a neutralizer, and then water is added for homogeneous emulsification. The parameters of homogeneous emulsification are not particularly limited and can be adjusted according to the actual situation. Preferably, the emulsification is performed under the condition of 2000±500r/min 30±10min, more preferably, the parameters of homogeneous emulsification are emulsification for 30min under the condition of 2000r/min.

The second aspect of the present invention provides an aqueous polyurethane for condoms, which is prepared by the preparation method described in the first aspect of the present invention.

The present invention will be described below through specific embodiments. It should be noted that the following specific embodiments are only for the purpose of illustration, and do not limit the scope of the present invention in any way. In addition, unless otherwise specified, conditions are not specifically described. Or the methods of the steps are all conventional methods, and the reagents and materials used can be obtained from commercial sources. Unless otherwise specified, the "parts", "parts", etc. described in the following examples and comparative examples are all parts by weight, and the relative molecular weights of the polymer polyols used in the following examples 1-6 are 2000.

Example 1

8 parts of dicyclohexylmethane diisocyanate, 22 parts of hexamethylene diisocyanate and 0.05 part of catalyst dibutyltin dilaurate are mixed to form the first component;

24 parts of polyethylene glycol and 40 parts of polytetramethylene ether glycol were dehydrated under vacuum at 120°C for 2 hours, and then mixed with 1 part of dimethylol butyric acid and 2 parts of diethylene glycol after cooling to 50°C. the second component;

The first component and the second component were injected into a reactor with a rotating speed of 200 r/min at 5 mL/min respectively, and stirred at the same time. After the injection was completed, the reaction was stirred at 90 ° C for 3 hours to generate a polyurethane with an average molecular weight of 1,000,000. prepolymer;

Then cooled to below 45°C, added 3 parts of triethylamine to neutralize dimethylol butyric acid, then added water to the reactor, and homogeneously emulsified for 30 minutes at 2000 r/min to form a stable aqueous polyurethane emulsion.

FIG. 2 shows the particle size distribution diagram of the water-based polyurethane emulsion in this example. It can be seen that the particle size of the water-based polyurethane is relatively uniform, and the average particle size is about 126 nm.

The water-based polyurethane prepared in this example has the characteristics of super softness and high elasticity. Specifically, it has good resilience, its 100% constant elongation modulus is 0.6MPa, and its elastic recovery rate is close to 100 when stretched at 600%. %.

Example 2

22 parts of dicyclohexylmethane diisocyanate, 8 parts of hexamethylene diisocyanate and 0.05 part of catalyst dibutyltin dilaurate are mixed to form the first component;

24 parts of polytetramethylene ether glycol and 40 parts of polyethylene glycol were dehydrated under vacuum at 120°C for 2 hours, and then cooled to 50°C with 1 part of dimethylolpropionic acid and 2 parts of 2 methyl 1, 3 propylene glycol forms the second component;

The first component and the second component were injected into the reactor with a rotating speed of 200r/min at 5mL/min, and the first component and the second component were stirred and reacted in the 90°C reactor for 3 hours, and the average molecular weight was 900000 polyurethane prepolymer;

Then cooled to below 45°C, added 3 parts of triethylamine to neutralize dimethylolpropionic acid, then added water to the reactor, and homogeneously emulsified for 30min at 2000r/min to form a stable aqueous polyurethane emulsion.

The water-based polyurethane prepared in this example has the characteristics of super softness and high elasticity, and has good resilience. Its 100% modulus at constant elongation is 0.7 MPa, and the elastic recovery rate is close to 100% when stretched by 600%.

Example 3

22 parts of 4,4'-diphenylmethane diisocyanate, 8 parts of hexamethylene diisocyanate and 0.05 part of catalyst dibutyltin dilaurate were mixed to form the first component;

24 parts of polytetrahydrofuran glycol and 40 parts of polytetramethylene ether glycol were dehydrated under vacuum at 120 °C for 2 hours, and after cooling to 50 °C, mixed with 1 part of dimethylol butyric acid and 2 parts of 1,3 propylene glycol forming a second component;

The first component and the second component were injected into the reactor with a rotating speed of 200r/min at 5mL/min, and the first component and the second component were stirred and reacted in the 90°C reactor for 3 hours, and the average molecular weight was 800000 polyurethane prepolymer;

Then cooled to below 45°C, added 3 parts of triethylamine to neutralize dimethylol butyric acid, then added water to the reactor, and homogeneously emulsified for 30 minutes at 2000 r/min to form a stable aqueous polyurethane emulsion.

The water-based polyurethane prepared in this example has the characteristics of super softness and high elasticity. Specifically, it has good resilience, its 100% constant elongation modulus is 0.8MPa, and its elastic recovery rate is close to 100% when stretched at 600%. .

Example 4

8 parts of 4,4'-diphenylmethane diisocyanate, 22 parts of hexamethylene diisocyanate and 0.05 part of catalyst dibutyltin dilaurate are mixed to form the first component;

24 parts of polytetrahydrofuran diol and 40 parts of polytetramethylene ether glycol were dehydrated under vacuum at 120 ° C for 2 hours, and after cooling to 50 ° C, 1 part of dimethylol butyric acid and 2 parts of 2 methyl 1, 3 propylene glycol is mixed to form the second component;

The first component and the second component were injected into the reactor with a rotating speed of 200r/min at 5mL/min, and the first component and the second component were stirred and reacted in the 90°C reactor for 3 hours, and the average molecular weight was 800000 polyurethane prepolymer;

Then cooled to below 45°C, added 3 parts of triethylamine to neutralize dimethylol butyric acid, then added water to the reactor, and homogeneously emulsified for 30 minutes at 2000 r/min to form a stable aqueous polyurethane emulsion.

The water-based polyurethane prepared in this example has the characteristics of super softness and high elasticity. Specifically, it has good resilience, its 100% constant elongation modulus is 0.8MPa, and its elastic recovery rate is close to 100% when stretched at 600%. .

Example 5

8 parts of 4,4'-diphenylmethane diisocyanate, 22 parts of cyclohexylmethane diisocyanate and 0.05 part of catalyst dibutyltin dilaurate are mixed to form the first component;

24 parts of polyethylene glycol and 40 parts of polytetramethylene ether glycol were dehydrated under vacuum at 120 °C for 2 hours, and then mixed with 1 part of dimethylol butyric acid and 2 parts of 1,3 propylene glycol after cooling to 50 °C forming a second component;

The first component and the second component were injected into the reactor with a rotating speed of 200r/min at 5mL/min, and the first component and the second component were stirred and reacted in the 90°C reactor for 3 hours, and the average molecular weight was 800000 polyurethane prepolymer;

Then cooled to below 45°C, added 3 parts of triethylamine to neutralize dimethylol butyric acid, then added water to the reactor, and homogeneously emulsified for 30 minutes at 2000 r/min to form a stable aqueous polyurethane emulsion.

The water-based polyurethane prepared in this example has the characteristics of super softness and high elasticity. Specifically, it has good resilience, its 100% constant elongation modulus is 0.8MPa, and its elastic recovery rate is close to 100% when stretched at 600%. .

Example 6

8 parts of cyclohexylmethane diisocyanate, 22 parts of 4,4'-diphenylmethane diisocyanate and 0.05 part of catalyst dibutyltin dilaurate are mixed to form the first component;

24 parts of polytetrahydrofuran diol and 40 parts of polytetramethylene ether glycol were dehydrated under vacuum at 120 ° C for 2 hours, and after cooling to 50 ° C, 1 part of dimethylol butyric acid and 2 parts of 2 methyl 1, 3 propylene glycol is mixed to form the second component;

The first component and the second component were injected into the reactor with a rotating speed of 200r/min at 5mL/min, and the first component and the second component were stirred and reacted in the 90°C reactor for 3 hours, and the average molecular weight was 800000 polyurethane prepolymer;

Then cooled to below 45°C, added 3 parts of triethylamine to neutralize dimethylol butyric acid, added water to the reactor, and homogeneously emulsified for 30min at 2000r/min to form a stable aqueous polyurethane emulsion.

The water-based polyurethane prepared in this example has the characteristics of super softness and high elasticity. Specifically, it has good resilience, its 100% constant elongation modulus is 0.9MPa, and its elastic recovery rate is close to 100% when stretched 600%. .

Example 7

10 parts of dicyclohexylmethane diisocyanate, 15 parts of hexamethylene diisocyanate, 0.05 part of bismuth isooctanoate and 0.05 part of bismuth neocaprylate are mixed to form the first component;

30 parts of polyethylene glycol (molecular weight 2500) and 30 parts of polytetramethylene ether glycol (molecular weight 2500) were dehydrated under vacuum at 90°C for 3 hours, and then cooled to 50°C with 1.5 parts of dimethylol. butyric acid and 1.5 parts of 1,3 propylene glycol are mixed to form the second component;

The first component and the second component were injected into a reactor with a rotating speed of 150 r/min at 8 mL/min respectively, and stirred at the same time. After the injection was completed, the reaction was stirred at 80 ° C for 4 hours to generate a polyurethane pre-polymer with an average molecular weight of 1,000,000. aggregate;

Then cooled to below 45°C, added 2 parts of triethanolamine to neutralize dimethylol butyric acid, then added water to the reactor, and homogeneously emulsified for 20min at 2500r/min to form a stable aqueous polyurethane emulsion.

The water-based polyurethane prepared in this example has the characteristics of super softness and high elasticity. Specifically, it has good resilience, its 100% constant elongation modulus is 0.7MPa, and its elastic recovery rate is close to 100% when stretched 600%. .

Example 8

14 parts of 4,4'-diphenylmethane diisocyanate, 14 parts of hexamethylene diisocyanate, and 0.2 parts of catalyst dibutyltin dilaurate were mixed to form the first component;

25 parts of polytetrahydrofuran diol (molecular weight of 3000) and 45 parts of polytetramethylene ether glycol (molecular weight of 3000) were dehydrated under vacuum at 100°C for 2.5h, and then cooled to 50°C with 2 parts of dihydroxy Methylpropionic acid and 2 parts of 2 methyl 1,3 propylene glycol are mixed to form the second component;

The first component and the second component were injected at 10 mL/min into a reactor with a rotating speed of 300 r/min, and stirred at the same time. After the injection was completed, the reaction was stirred at 85 ° C for 3 hours to generate a polyurethane pre-polymer with an average molecular weight of 1,000,000. aggregate;

Then cooled to below 45°C, added 2.5 parts of N,N-diisopropylethylamine to neutralize dimethylolpropionic acid, then added water to the reactor, and homogeneously emulsified for 40min under the condition of 1500r/min, Forms stable aqueous polyurethane emulsions.

The water-based polyurethane prepared in this example has the characteristics of super softness and high elasticity. Specifically, it has good resilience, its 100% constant elongation modulus is 0.7MPa, and its elastic recovery rate is close to 100% when stretched at 600%. .

Comparative Example 1

8 parts of dicyclohexylmethane diisocyanate, 22 parts of isophorone diisocyanate and 0.05 part of catalyst dibutyltin dilaurate are mixed to form the first component;

24 parts of polyethylene glycol and 40 parts of polytetramethylene ether glycol were dehydrated under vacuum at 120°C for 2 hours, and then mixed with 1 part of dimethylol butyric acid and 2 parts of diethylene glycol after cooling to 50°C. the second component;

The first component and the second component were injected into the reactor with a rotating speed of 200r/min at 5mL/min, and the first component and the second component were stirred and reacted in the 90°C reactor for 3 hours, and the average molecular weight was 1,000,000 polyurethane prepolymer;

Then cooled to below 45°C, added 3 parts of triethylamine to neutralize dimethylol butyric acid, added water to the reactor, and homogeneously emulsified for 30min at 2000r/min to form a stable aqueous polyurethane emulsion.

The water-based polyurethane prepared in this example has low resilience, its 100% constant elongation modulus is 1.5MPa, and the elastic recovery rate is close to 100% when stretched to 400%.

Comparative Example 2

8 parts of dicyclohexylmethane diisocyanate, 22 parts of hexamethylene diisocyanate and 0.05 part of catalyst dibutyltin dilaurate are mixed to form the first component;

24 parts of polyethylene glycol (molecular weight 1000) and 40 parts of polytetramethylene ether glycol (molecular weight 1000) were dehydrated in vacuum at 120 ° C for 2 hours, and then cooled to 50 ° C with 1 part of dimethylol butane The acid and 2 parts of diethylene glycol are mixed to form the second component;

The first component and the second component were injected into the reactor with a rotating speed of 200r/min at 5mL/min, and the first component and the second component were stirred and reacted in the 90°C reactor for 3 hours, and the average molecular weight was 1,000,000 polyurethane prepolymer;

Then cooled to below 45°C, added 3 parts of triethylamine to neutralize dimethylol butyric acid, then added water to the reactor, and homogeneously emulsified for 30 minutes at 2000 r/min to form a stable aqueous polyurethane emulsion.

The waterborne polyurethane prepared in this comparative example has low resilience, its 100% constant elongation modulus is 1.6MPa, and the elastic recovery rate is only close to 100% when stretched 400%.

Comparative Example 3

In this comparative example, the composition of the raw materials is the same as that of Example 1, and the difference is only in that the preparation process is different. The specific preparation method of this comparative example is as follows:

24 parts of polyethylene glycol and 40 parts of polytetramethylene ether glycol were dehydrated in vacuum at 120 °C for 2 hours, and after cooling to 50 °C, 8 parts of dicyclohexylmethane diisocyanate and 22 parts of hexamethylene were added. Add 0.05 part of catalyst dibutyltin dilaurate to diisocyanate, then heat up to 90°C and stir for 2h in a reactor with a rotating speed of 200r/min; then cool down to 50°C, add 1 part of dimethylol butyric acid and 2 parts of Diethylene glycol continued to react for 1h to generate a polyurethane prepolymer with an average molecular weight of 1,000,000;

Then cooled to below 45°C, added 3 parts of triethylamine to neutralize dimethylol butyric acid, then added water to the reactor, and stirred at a high speed for 30 minutes at 2000 r/min to form a stable aqueous polyurethane emulsion.

The waterborne polyurethane prepared in this comparative example has low resilience, its 100% constant elongation modulus is 1.4MPa, and the elastic recovery rate is only close to 100% when stretched by 400%.

test case

The water-based polyurethane prepared in Examples 1-8 and Comparative Examples 1-3 was made into polyurethane condoms, and the condoms prepared were subjected to performance testing and testing according to GB7544-1992, GB/T7546-1992 and GB/T7547-1992. The results are shown in Table 1 below.

For the preparation process of water-based polyurethane condoms, please refer to the preparation method of water-based polyurethane condoms disclosed in CN103640133A, which is specifically as follows: cleaning and drying a stainless steel mold, immersing the mold in the nano-scale water-based polyurethane cross-linked particle emulsion, taking out the glue and drying, and drying the treated mold Immerse in the water-based polyurethane emulsion, take out the glue and dry it to obtain a water-based polyurethane film on the surface of the mold. The open end of the water-based polyurethane film on the mold surface is crimped, and the treated mold is immersed in hot water of 50±5℃. After drying, it is then immersed in a release agent, taken out and dried, and electrical inspection is performed on the treated film by a dry method.

Table 1 Test results of condom performance

As can be seen from the test results in Table 1, the thickness of the polyurethane condom made by the preparation process in the present invention is as low as below 0.015mm, and the strength is about twice that of the latex condom (the latex is generally 10-15MPa); It can be seen that the higher the molecular weight of the waterborne polyurethane, the closer the 100% constant elongation modulus (flexibility) of the obtained polyurethane condom is to the performance of the latex condom (about 0.7MPa). This shows that the ultra-soft and high-elastic water-based polyurethane obtained by the present invention not only maintains the ultra-thin and high-strength characteristics of polyurethane condoms, but also has flexibility surpassing that of latex condoms, and has simple process and excellent comprehensive performance.

From the comparison of the test results of Comparative Example 1 and Example 1, it can be seen that the flexibility of Comparative Example 1 is not as good as that of Example 1, indicating that the isocyanate selects the water-based polyurethane prepared by the combination of hexamethylene diisocyanate with softer molecules and easier internal rotation. The overall performance of the compound is more excellent; in Comparative Example 1, the main reason is that the isophorone diisocyanate used has a cis- and trans-asymmetric structure, which can increase the intermolecular repulsion and form steric hindrance, so that the polyurethane forms a cross-sectional structure. The networked structure will increase the hardness of the product film formation, and the flexibility is poor.

It can be seen from the test results of Comparative Example 2 and Example 1 that the flexibility of Comparative Example 2 is also not as good as that of Example 1, indicating that the comprehensive performance of the water-based polyurethane prepared by the combination of polyether diols with a molecular weight of 2000 is more excellent; and In Comparative Example 2, since the polyether diol with a molecular weight of 1000 is used as the soft segment of the polyurethane, although its reactivity with polyisocyanate is relatively high, the small molecular polyether has a too short segment length, and the free rotation space of the molecular chain decreases, which will lead to a decrease in the free rotation space of the molecular chain. The softness of the emulsion is greatly reduced and the hardness of the film is increased.

From the test results of Comparative Example 3 and Example 1, it can be seen that the flexibility of Comparative Example 3 is not as good as that of Example 1, which shows that after forming the first component and the second component respectively, the raw materials are controlled by slow mixing to make them more flexible. The prepolymerization reaction occurs gradually, and the obtained water-based polyurethane has good flexibility and elasticity, and has more excellent comprehensive properties.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (10)

1. a preparation method for the water-based polyurethane of condom, is characterized in that, comprises the following steps: providing a first component consisting of 25-30 parts by weight of isocyanate monomer and 0.05-0.2 parts by weight of catalyst; The second component is provided, which is composed of 60-70 parts by weight of polymer polyol after vacuum dehydration, 1-2 parts by weight of hydrophilic monomer and 1-2 parts by weight of small molecule chain extender; The first component and the second component are slowly added to the reaction vessel, and the reaction is stirred at 80-90° C. to obtain an ultra-high molecular weight polyurethane prepolymer; Cool the system to below 45°C, add 2-3 parts by weight of a neutralizing agent for neutralization, and then add water for homogeneous emulsification to obtain a stable aqueous polyurethane emulsion. 2. The preparation method according to claim 1, wherein the isocyanate monomer is selected from the group consisting of dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate any combination of the two. 3. The preparation method of claim 1, wherein the catalyst is selected from the group consisting of bismuth carboxylate mixture and dibutyltin dilaurosilicate. 4. The preparation method according to claim 1, wherein the relative molecular mass of the polymer polyol is 2000-3000. 5. preparation method as claimed in claim 1, is characterized in that, described polymer polyol is selected from polytetrahydrofuran diol, polytetramethylene ether glycol, the combination of one or both of polyethylene glycol . 6 . The preparation method according to claim 1 , wherein the vacuum dehydration process is specifically: vacuum dehydration of the polymer polyol at 90-120° C. for 2-3 hours. 7 . 7. The preparation method of claim 1, wherein the hydrophilic monomer is selected from the group consisting of dimethylol butyric acid and dimethylol propionic acid. 8. preparation method as claimed in claim 1 is characterized in that, described neutralizing agent is selected from triethylamine, N,N-diisopropylethylamine, triethanolamine, N,N-dimethylethanolamine A sort of. 9 . The preparation method of claim 1 , wherein the small molecule chain extender is selected from the group consisting of 1,3 propylene glycol, diethylene glycol, diethylaminoethanol, and 2 methyl 1,3 propylene glycol. 10 . 10. A water-based polyurethane for condoms, characterized in that, it is prepared by the preparation method according to any one of claims 1-9.

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